JWT Generator

Build, sign, and generate JSON Web Tokens (JWT) using HMAC SHA-256 (`HS256`), `HS384`, or `HS512` algorithms. Customize header tags, expiration timestamps (`exp`), issued-at (`iat`), sub, role claims, and secret signing keys.

Why Use This Tool?

• REST API & OAuth Testing: Generate mock JWT authentication tokens for frontend testing and API endpoint debugging.
• Custom Role Claim Inspection: Test custom claims (`role: admin`, `tenant_id`) in token payloads.
• Local Private Key Signing: Sign JWT tokens locally without sharing secret keys with external online generators.

How to Use

1. Edit Header JSON (default: `{"alg": "HS256", "typ": "JWT"}`).
2. Edit Payload JSON (e.g. `{"sub": "123", "name": "Admin", "exp": 1770000000}`).
3. Enter Secret Key and click Generate JWT Token.

Real Working Example

Input:

Payload: {"sub": "user_123", "role": "admin"} | Secret: "super_secret_key_2026" | Alg: HS256

Output Result:

Generated JWT Token:
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiJ1c2VyXzEyMyIsInJvbGUiOiJhZG1pbiJ9.7x9Y2m...

Important Technical Details & Security Standards

• RFC 7519 JWT Standard Compliance: Encodes header and payload as Base64URL strings joined by dots (`header.payload.signature`).
• Web Crypto HMAC Signing: Computes `HMAC-SHA256(Base64URL(Header) + "." + Base64URL(Payload), Secret)` signature.
• 100% Client-Side Engine: Secrets and tokens remain 100% private in browser memory.

Related Security & Crypto Tools

• JWT Parser: Decode and inspect JWT tokens.
• HMAC Generator: Compute HMAC signatures.
• Token Generator: Generate random tokens.